491 years ago today, Princess Mary Tudor (Henry VIII's little sister) married King Louis XII of France. Mary was 18 and reputed to be the most beautiful princess in the world. Louis was 52, a little sickly, and, uh, not quite such a catch.

While almost everyone knows about Henry VIII and his six wives, few people know anything at all about his equally passionate sisters. Not to go all "her"story on you, but Mary was the star of one of the best royal romance stories of all time and it's worth a retelling.

Before Mary's marriage, she fell in love with Charles Brandon. Brandon was one of Henry VIII's best friends. He reciprocated Mary's feelings but a marriage between the two of them was unthinkable. She was a princess and her marriage would be used to further England's relations with France or Spain. But, Mary, to her credit, refused to just accept that her fate was not in her own hands. So, before she traveled to France she extracted a promise from her brother (a promise he most certainly didn't intend to keep): she'd marry Louis, but when he died she'd marry the man of her choosing.

After just three months of marriage, Louis did die. Mary was isolated for six weeks to make sure she wasn't carrying a potential heir to the throne (she wasn't). The only man who was allowed in her presence was the new king, Francois I. During their time together, Mary confessed her feelings for Brandon and she and Francois hatched a plot. As one of Henry's closest friends and advisors, Brandon would be sent to France to fetch Mary. When he arrived, Francois arranged for a meeting between the two and Mary did the rest, convincing Brandon to defy his king and be with her.

"In the small chapel of the Palais de Cluny, Mary Tudor did the unimaginable for most princesses, she married the man she chose. When Henry found out about the marriage, he was furious. However, Mary was his favorite sister and Charles was an old friend, and the couple was soon forgiven."

Throughout her life, Mary was referred to as the "French Queen", a constant reminder that she had married beneath her, but also, one would imagine, a constant reminder that she also defied the world and had her heart's desire. Sadly, Mary died of cancer when she was just 37. Although Henry VIII's will declared that Mary's heirs inherit the throne before their other sister Margaret's heirs, it didn't turn out that way. The closest the descendents of Mary got was with her granddaughter, the unfortunate Lady Jane Grey.